Parking locks, which are designed to prevent a motor vehicle with an automatic transmission from inadvertently rolling away, are subject to various criteria, among which in particular a rejection condition at higher vehicle speeds must be fulfilled. In general a parking lock is designed for a particular drop-in speed, i.e. a limit speed of the vehicle at which the locking pawl can still just drop into a tooth gap so that the locked position is reached. Above this limit speed it must be ensured that the pawl tooth does not drop into a tooth gap, but is kept out by virtue of the teeth or tooth contour. The rejection of the locking pawl above the drop-in speed is known as “ratcheting” and, depending on the tooth geometry, results in a dynamic that damages the components. It has therefore already been proposed that by virtue of a suitable tooth carrier, the rejection of the locking pawl takes place as gently as possible.
EP 1 895 206 B1 discloses a parking lock device for a motor vehicle transmission, which comprises a parking lock gearwheel with circumferential teeth and a parking lock pawl with a pawl tooth or catch which engages in a tooth gap of the parking lock gearwheel to lock a transmission output shaft. At the crown of the pawl tooth or catch as viewed in the rotation direction of the parking lock gearwheel, the pawl tooth or catch has a rounded tooth contour which follows a defined logarithmic function or a defined exponential function. The shape of the logarithmic or exponential function is characterized by varying curvature, such that the curvature is most pronounced in the area of the forward tooth edge and least so in the area of its rear edge. Thus, as viewed in the rotational direction of the parking lock gearwheel the curvature of this tooth contour decreases with the width of the tooth. Due to this rounding of the tooth, above the drop-in speed and up to a maximum speed of the vehicle the locking pawl should be rejected with a low impulse magnitude, in particular with an approximately constant magnitude. Disadvantageously, however, the impulse exerted on the parking lock pawl during ratcheting depends very much on the exact position of the contact point at which the pawl tooth of the parking lock pawl meets a tooth of the parking lock gearwheel. The resulting scatter can be perceived by the driver of the vehicle as annoying.